IOS:
For the best experience users should have an iPhone 8 which has the A11 Bionic chip, and the latest IOS version. The difference in Appraisal Grid App speed is noticeable between the various models due to the processing speeds. The app will work with earlier model iPhones albeit at a slower speed. The absolute minimum iPhone model needed is undetermined.
iPhone processor information:
iPhone 7 – A10 Fusion chip
iPhone 8 – A11 Bionic chip
iPhone XR – A12 Bionic chip
iPhone 10XS – A12 Bionic chip
iPhone 10 XS Max – A12 Bionic chip
What’s the difference in speed between the A11 and the A12?
The A12 consumes 40% less power than the A11, but is 15% faster than the A11 and 25% faster than the A10.
Android:
To be determined. (2 years back)